Fiber-Optic Illumination for Microscope

In a simple but very effective method for providing intense illumination of an opaque specimen under a microscope, light is supplied via an optical fiber. This system eliminates the need for traditional Köhler-type vertical illumination system components, such as beam splitters and lenses, and is easily adaptable to vacuum environments. The output end of the fiber is placed at the edge of the microscope objective back lens (see figure), near the pupil. The light from the fiber passes down through the objective lens, which concentrates the light onto the specimen.